Commercial and industrial working fluid media for thermodynamic cycle systems are fluids which are generally either pure compounds, azeotropes, or nonazeotropes (zeotropes).
Many such mixtures are known in the art as illustrated, for example, in the following references:
Lewis, U.S. Pat. No. 2,641,580, granted Jun. 9, 1953, for "Azeotropic Refrigerant Composition of 1,1-Difluoroethane and Monochloropentafluoroethane".
Fuderer, U.S. Pat. No. 3,203,194, granted Aug. 31, 1965, for "Compression Process for Refrigeration".
Orfeo et al., U.S. Pat. No. 4,303,536, granted Dec. 1, 1981, for "Nonazeotropic Refrigerant Composition Containing Monochlorodifluoromethane, And Method Of Use".
Nikolsky et al., U.S. Pat. No. 4,603,002, granted Jul. 29, 1986, for "Method And Cooling Agent For Freezing And Storing Products".
Japanese Patent Kokai 52-70466, published in 1977 to Daikin Kogyo KK, for "Low Boiling Point Refrigerant Compositions".
B.C. Langley, "Refrigeration and Air Conditioning", 2d ed. 1982.
French Patent 2,130,556 (VEB Monsator Haushalt grossgeratekombinat).
French Patent 2,177,785 (VEB Monsator Haushalt grossgeratekombinat).
French Patent 2,607,144 (Institute Francaise du Petrole).
M. F. Bouzianis, "Chlorofluorocarbons And Their Alternatives"(Arthur D. Little 1988).
D. J. Bateman et al., "Refrigerant Blends for the Automotive Air Conditioning Aftermarket," SAE Technical Paper Series 900216 (SAE International Congress and Exposition - Detroit, Mich. Feb. 26-Mar. 2, 1990).
"ASHRAE Terminology of Heating, Ventilation, Air-conditioning and Refrigeration", 2nd ed. (American Society of Heating, Refrigeration, and Air-Conditioning Engineers Inc. 1991).
Nonazeotropic refrigeration media ("NARMs") in particular are attractive because, during the thermodynamic cycle process, they absorb more heat during the isobaric evaporation stage, release more heat during the isobaric condensation stage, and do more work during the expansion process or need less work during the compression stage than do either single-compound or azeotropic working fluid media under comparable external conditions. In other words, NARMs have a higher "coefficient of performance" (defined hereinbelow) in an inverse thermodynamic cycle device, and higher work efficiency in a normal thermodynamic cycle device.
However, known nonazeotropic working fluid media have serious drawbacks stemming from the fact that in mechanical refrigeration, air conditioning, heat pump and hot-fluid power generation systems, vaporization loss of such media is unavoidable. This results not only in changes in the concentrations of the components of the liquid phase of the working fluid media, but also results in a decrease in the weight or mass of the working fluid medium. In turn, there is a continuous decrease in the Coefficient of Performance ("COP") and a decrease in the power generating efficiency of hot-fluid power generation systems. (The term "COP" as used herein is the ratio of the rate of net energy removal from the environment (in the case of a refrigerant) or net energy output (in the case of a heating or power generating system) to the total energy input expressed in consistent units and rating conditions). Because of this, it is necessary to replenish the working fluid to its original weight level.
But with conventional NARMs, the replenished working fluid medium has a different composition than the original working medium after vaporization losses. This result stems from changes in the system concentration, which are attributable to recharging with original nonazeotropic medium, which mixes with a partially depleted liquid working fluid whose composition had changed due to zeotropic vaporization. Such mixing, therefore, leads to a different concentration of the final working fluid medium than the original working medium, and results in a continuing decrease in the COP and a decrease in power generating efficiency.
Consequently, the changes in proportions (concentrations) of the components of the working fluid medium make its useful life much shorter than if its composition had remained unchanged. Inevitably the entire working fluid medium has to be discharged and replaced. Because conventional NARMs have ozone depletion potential ("ODP"), and are toxic, especially when discharged in such large quantities, the continued use of conventional NARMs is having and will continue to have deleterious effects on the ozone layer and the environment. To avoid such problems and drawbacks requires large investments in recycling systems or the discovery of new ways of handling conventional NARMs that have to be discharged in this way. Neither approach is entirely satisfactory from a technical, economic or environmental standpoint.
Therefore, a need definitely exists for nonazeotropic working fluid media useful in thermodynamic cycle systems and having extended useful working life, with little decrease in COP and little decrease in power generating efficiency during repeated vaporization loss and replenishment cycle processes.
Accordingly, it is an object of the present invention to provide nonazeotropic fluid working media for use in thermodynamic compression cycle systems, which media are improved with respect to anti-vaporization loss properties with respect to the effect on COP of changes in the composition of the medium resulting from repeated vaporization loss and replenishment cycles.
Another object is to provide refrigeration, air conditioning, heating and power generation systems using hot fluid and the like devices employing the aforesaid improved, nonazeotropic working fluid media.
Another object is to provide a thermodynamic engineering device operated as a thermodynamic cycle system employing a nonazeotropic working fluid medium having improved vaporization loss stability.
Another object is to provide an air conditioning device operated as a thermodynamic cycle system employing a nonazeotropic working fluid medium having improved vaporization loss stability.
Another object is to provide a heating device operated as a thermodynamic cycle system employing a nonazeotropic working fluid medium having improved vaporization loss stability.
Yet another object is to provide a method of transferring heat by means of a thermodynamic compression cycle utilizing the aforesaid improved non-azeotropic working media of the present invention.
These and other objects of the invention can be understood and achieved by reference to the following disclosure, drawings and claims.